(a) Field of the Invention
The present invention relates to a dynamic resource allocating apparatus and method, and more particularly, to a dynamic resource allocating method and apparatus capable of canceling inter-cell noise in a cellular communication system.
(b) Description of the Related Art
In general, in a wireless communication system, the entire service area is divided into a plurality of cells to constitute multiple cells in order to increase system capacity. A base station (BS) is installed in each cell to provide a service to a terminal located within the cell.
In such a cellular system, in order to increase system capacity, frequency usage efficiency is required to be maximized, and to this end, each cell is designed to commonly use the entire frequency band. Thus, in the case in which neighboring cells commonly use the same frequency band, subchannels including an orthogonal frequency are allocated by users within one cell, causing no interference, but interference occurs between cells. This is known as inter-cell interference.
In particular, in case of a terminal located in a central area of a cell, strength of a signal received from a different cell is weak and a signal received from a serving cell is strong, inter-cell interference is not problematic, but in case of a terminal located in a boundary area of a cell, strength of a signal received from a neighboring cell is strong and a signal received from a serving cell is weak, having a low reception signal-to-noise ratio (SNR), which results in significant degradation of communication performance.
Thus, in order to solve the problem, a fractional frequency reuse (FFR) scheme has been proposed.
The FFR scheme is a scheme in which resource allocation for canceling inter-cell interference is performed in a frequency domain, and in addition, a fractional time reuse (FTR) scheme in which resource allocation is performed in a time domain has also been proposed.
According to the FFR scheme, a frequency domain is divided in a radio resource structure defined by two dimensional domains of time and frequency to cancel inter-cell interference. Further, the FTR scheme, relative to the FFR scheme, is a scheme in which a time domain is divided and a resource is allocated to a neighboring cell, thus canceling inter-cell interference.
Even in the FTR scheme, various methods used in the FFR scheme may also be used in the same manner.
However, having a configuration in which allocated resources are fixed, such a resource allocation scheme has difficulty in coping with a change in a load distribution within a cell or between cells.
Namely, if user load distributions in cells are even, there is no problem, but when user load distributions in cells are not even, one cell may be short of a resource, while the others may have remaining resources because the resources are not in use. Also, even within a cell, when load distributions in the center of the cell and the boundary thereof are not even, allocated resources may not be used or resources may be insufficient, which may result in failure of providing a service properly.